(a) Field of the Invention
The present invention relates to a polysilicon resistor, a reference voltage circuit including the same, and a method for manufacturing the polysilicon resistor.
(b) Description of the Related Art
A resistor has a resistance value that varies according to increase/decrease of the resistor. A conventional resistor formed using doped polysilicion, that is, a polysilicon resistor has a resistance value variation characteristic (i.e., a temperature characteristic of the resistor) according to temperature variation, and the temperature characteristic of the resistor is changed according to a doping type.
For example, the resistance value may be decreased as the temperature increases when a polysilicon layer is N-type doped, and the resistance value may be increased as the temperature increase when the polysilicon layer is P-type doped.
This causes a reference voltage value of a bandgap reference circuit that generates a predetermined level of a reference voltage to be increased or decreased according to a temperature.
In addition, a BJT circuit is additionally provided in the bandgap reference circuit to compensate the variation of the reference voltage value of the bandgap reference circuit, thereby causing an increase of cost and size.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.